Apple's terms of service prohibit doing exactly this. There's a most-favourable-price clause.

Speaking as someone with actual experience in this - DirectX is a monumental improvement over OpenGL; there's more to it than just being able to look at the underlying code (and frankly, 90% of both are just shims to pump commands into the drivers which is where the real magic happens -- drivers which generally tend to be very closed.)

Start with;
- A (arguably) better shading language (HLSL vs GLSL - I tend to find HLSL is easier to work with)
- A scenegraph representation that is not built around a 1980's pre-acceleration stack based renderer. (e.g. Objects are represented as full OO objects - complete with materials, rather than a matrix pushed onto a stack followed by a few vertex buffer array calls)
- A suite of excellent debugging utilities - which give you useful feedback (looking at the code != the value of a good debugger suite)

Leaving the 'free software' arguments aside, DirectX is better - by virtue of the fact that it's kept up to date with modern programming techniques. OpenGL needs to be replaced or at least significantly overhauled -- something which Khronos has not in the past actually been willing to do. OpenGLES improves the spec marginally, but it really needs a replacement to be on par with the ease and power DirectX offers you with far less effort.

That said; if anyones doing things at the DX/OGL level, they probably need to be hit over the head - anyone serious is using one of the many decent engines out there.

My first guess would say no; and this is an uninformed opinion - but that is probably structured as a non-poach agreement, e.g. IBM is not allowed to poach employees from CDI.

That does tend to be legal - although the punishment is relatively thin. IBM would only have to pay for a recruiter to find someone of similar calibre to CDI in damages if it ever went to court/arbitration/settlement.

Yes and no - the less skilled the job, the harder you have to deal with employee turnover.

For engineers though, providing you are running things well, you'll usually only have a big burst of turnover around the national holiday in March, when everyone gets paid a 13th salary as a bonus. The rest of the year though, everyone just waits until March so they don't lose their bonus. Turnover seems to be getting better too however - we only lost 2 from a team of 20 this past March (compared to 4-5 the previous year, and 5-7 the year before.)

Unity does this actually - all shaders are written in Cg/HLSL, then cross-compiled to GLSL for OpenGL & OGLES. It's a surprisingly pleasant workflow - especially with their Surface Shader framework.

Well, intersexed persons make a bit of a mess of that. Since you can have both sets physical features in various strengths in some people. That's been where the biggest controversies have come up in recent history.

Yes - it's basically just compiling small .NET programs from your input -- which tend to be pretty portable. You should only run into problems if you use new features that aren't available in older environments (but - I'm pretty sure the latest version of .NET can be installed on XP, so that might be a moot point.)